Azuma Akifumi, Kobayashi Shozo
Division of Grape and Persimmon Research, Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization (NARO), Higashihiroshima, Hiroshima 739-2494, Japan.
Division of Grape and Persimmon Research, Institute of Fruit Tree and Tea Science, National Agriculture and Food Research Organization (NARO), Higashihiroshima, Hiroshima 739-2494, Japan.
Plant Sci. 2022 Sep;322:111341. doi: 10.1016/j.plantsci.2022.111341. Epub 2022 May 27.
Black-skinned and red-fleshed grape 'Brazil' is a bud sport of rosy-skinned 'Benitaka'. 'Brazil' has a much higher anthocyanin content in the skin than that of 'Benitaka' and is characterized by the accumulation of anthocyanins in the flesh. Our genomic analysis of the VvMYBA loci, which regulate anthocyanin biosynthesis, suggested that the difference in skin and flesh color between 'Brazil' and 'Benitaka' cannot be explained by genomic alteration at the loci. Expression levels of VvMYBA1 and anthocyanin biosynthesis-related genes in skin and flesh were significantly higher in 'Brazil' than in 'Benitaka' throughout berry development. DNA methylation levels in the 3' long terminal repeat (LTR) of a retrotransposon in the upstream region of VvMYBA1 allele were clearly higher in the skin and flesh of 'Benitaka' than in those of 'Brazil' throughout berry development. These findings suggest that a dramatic decrease in DNA methylation level in the 3' LTR of the retrotransposon in the VvMYBA1 allele in 'Brazil' increases the expression levels of VvMYBA1 and anthocyanin accumulation in skin and flesh. Our findings also suggest that skin and flesh colors are inherited together and vary depending on the presence or absence of the VvMYBA1 allele.
黑皮红肉葡萄“巴西”是红皮葡萄“红地球”的芽变品种。“巴西”果皮中的花青素含量远高于“红地球”，其特点是果肉中也积累了花青素。我们对调控花青素生物合成的VvMYBA基因座进行的基因组分析表明，“巴西”和“红地球”在果皮和果肉颜色上的差异无法用该基因座的基因组改变来解释。在整个浆果发育过程中，“巴西”果皮和果肉中VvMYBA1及花青素生物合成相关基因的表达水平均显著高于“红地球”。在整个浆果发育过程中，“红地球”果皮和果肉中VvMYBA1等位基因上游区域反转录转座子3'长末端重复序列（LTR）中的DNA甲基化水平明显高于“巴西”。这些发现表明，“巴西”中VvMYBA1等位基因反转录转座子3' LTR中DNA甲基化水平的显著降低增加了VvMYBA1的表达水平以及果皮和果肉中花青素的积累。我们的研究结果还表明，果皮和果肉颜色是一起遗传的，并且会因VvMYBA1等位基因的存在与否而有所不同。
